Shooting my 338 LM @ 2200 meter

Discussion in 'Extreme Long Range Hunting & Shooting (ELR)' started by Yrcan, Mar 3, 2012.

  1. Yrcan

    Yrcan Well-Known Member

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    I thought I should share my small experience shooting at real long range with my 338 Lapua.
    I have been shooting long range for the last 2 years now, nothing real serious, but after I bought myself a rifle and had it customised to my specs, things have gotten more complicated and my shooting skills has improved, alot.

    The rifle is a Rem 700 MLR Police. I removed the original barrel, too short in my opinion, and rebarreld the action with a LW barrel, being 32" long and 1.1" thick at the mussle. I also replaced the original stock with a AICS 1.5

    I have been writing alot about my shooting with it on a norwegian forum, similar to this, and I have posted various videos of shooting past 1000 meters, and some good groups at 100 and 300 meters. I have not shot on paper targets past 300 meter yet, but I'm shooting steel plates out to 1300 meters.

    There has been a discussion whether it is possible to shoot out to 2000 meters, and beyond. Some said it can't be done unless a whole lot of criterias are followed, and there has been alot of teori talk. I'm not the teoretic kinda guy, I like to take my rifle out to the field and actually test what is possible with my tools.

    Today, I tried for 2000 meters and beyond, shooting at at rock lying next to the waterline in a fjord here where I live. Weather was perfect so I went for it.
    I use Shooter, and it said I should dial 103.5 MOA for 2000 meters. I have 104 MOA in my scope (Millett LRS 5x25x56). Aimed 0.5 MIL left for spin and made the shot. Too short, I ended up at almost 6 MILS to reach the rock. My scope was at 14x so I guess it would be close to 10 MILS at 25x.

    I let the silencer cool down, and made another 5 shot trial at the rock. I did not mean to hit it, as it is difficult to actually see any impacts at that range, so I was hoping to hit the water right infront of it. I did, and it is easy to se that the bullets grouped well.
    I will get a big cardbord target out there soon, and get some bullet holes in it, to measure a 10 shot group. Then we will see what this caliber is all about.

    This is my favorite gun of all times, and when hunting season starts in september, I hope to shoot some deer at 1000 meters, and beyond.
    I shoot 300 grs SMK, using 88grs Vith N570 powder, pushing them at 861 m/sek. At 92 grs I get 910 m/sek, witch is pretty good for a standard 338 LM.

    Here is the video, I'm speaking in Norwegian, but I guess you can see what I try to do.

    338 Lapua Magnum @ 2200 meter.wmv - YouTube
     
  2. ICANHITHIMMAN

    ICANHITHIMMAN Well-Known Member

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    Pretty good I would not want to be standing infront of you. I think you need a bigger scope.
     

  3. sp6x6

    sp6x6 Well-Known Member

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    How many fish where killed in the filming of this video:D
     
  4. M67

    M67 Well-Known Member

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    I think you will splash that cardboard soaking wet!

    Now since i am virtually Yrcans theorethically inclined internet-devil-on-the-shoulder, can someone try to explain why Shooter so badly underpredicts the come-up on this shot?


    K
     
  5. Driftin

    Driftin Member

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    Nice, thanks for sharing.
     
  6. Shumba

    Shumba Well-Known Member

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    Shooter is a good program that works. Ballistic programs are not magic, they simply calculate complex mathematical formulas based on provided numbers. The calculations don't lie. If the come up does not match the real world trajectory the reason is in incorrect input. To add another issue to the equation is that there are variables that affect known variables, changing what you thought to be correct, especially at extreme range. Things like BC changes over the trajectory and shedding of velocity. Possibly a colder than normal day reducing the known MV of the bullet, headwind that was not taken into account. Maybe spin drift was not enabled along with a crosswind forcing the bullet down.......all of these are but a few things that could cause false results with any ballistics program. At ranges like that it really is near to impossible to know the true inputs. Hope this helps.
     
  7. load

    load Well-Known Member

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    another thing that effects bc is humidity. shooting directly over water the humidity will be alot higher than at the weather station. the velocity is also nearing the speed of sound. most bcs are taken at around 2700 fps bullets act differently at velocity. another may be Coriolis effects. at that range there could be more than one correction(depending on the direction shot)
     
  8. load

    load Well-Known Member

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    "I ended up at almost 6 MILS to reach the rock. My scope was at 14x so I guess it would be close to 10 MILS at 25x."

    I wonder if the poster realizes that the lrs-1 reads correct mil at 12.5 power. at 25 it reads 1/2 mils. at 14 you cant use the dots for mathematical calculations unless you know its exact measure (can be done by looking at a tape at set distance (like 100 yrds)gun)
     
  9. Yrcan

    Yrcan Well-Known Member

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    That's strange, but maybe true.
    But in the manual from Millett, it states that 1 MiL = 25x.

    I took a shot @ 1350 meters 2 weeks ago@ 25x, and used the dot's for holding the windage, it was spot on from what Shooter came up with.

    Maybe something is different with my new LRS-1. ???
     
  10. M67

    M67 Well-Known Member

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    Undoubtedly, the question is simply what variable is SO wrong?
    I have done my share of lobbing 308 and 6.5mm to "impossible" range, almost always "sighting in" on the spot, as temperature measuerement is by nose and ass, and pressure by weater forecast, etc.. the 6.5 becomes effectively unspottable beyond 1500m as we do not have desert sand here.
    However:

    I have been pestering Yrcan over this and i am convinced that all the normal variables are accounted for and used well within accuracy that should yield less than 1/10 of the error we are seeing.

    Running my ovn dope i get between 40.0 and 44.0 mil UP, considering the probable met/env at Yrcans site.
    Changing variables

    Temperature: 1°C is 0.015mil /
    Pressure: 1hPa is 0.044mil
    Direction: 90 vs 270° is 0.5mil
    headwind: 1m/s is 0.06mil
    velocity: 1m/s is 0.11mil
    Humidity: miniscule effect, and anyways close to 100% in all Yrcans shooting
    BC: 0.010 of G7 BC is 1.2mil (in comparison it is 0.3@1350m)
    Range: 10m is abouts 0.44mil

    As far as i can tell from experience with measuring all these variables, at distances beyond handheld lasers, range is by far the most challenging. I estimate Yrcans temp, press. and other measuerements to be accurate within 2-3units of measurement. Wind probably far better, as we can see there is very little wind anyway.
    Range has been remeasured using different maps, GPS, etc.
    For any probable error in variables other than BC, the range must be over 2300m, which it is not.

    Thus, as i see it we are left with BC, obviously very important at this flight time (5.3s)

    The question becomes then, does the G7 BC change with velocity, and does it change on the order of 0.02 units?
    Does it change at the speed of sound? After all the bullet is travelling 600m, and for 2 seconds, below the speed of sound. If this is the case, the only solution will be a custom drag model, or to tweak it with different BCs for different ranges, or to use a bullet that fits the existing drag model.
    Maybe the bullet enters a region of dynamic instability, and is coning , or some kind of limit cycle oscillatons - thus increasing drag?

    K
     
    Last edited: Mar 9, 2012
  11. Shumba

    Shumba Well-Known Member

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    My apologies as I do not know how to do the multiple quotes

    Quote:
    I estimate Yrcans temp, press. and other measuerements to be accurate within 2-3units of measurement. Wind probably far better, as we can see there is very little wind anyway.

    My impression in the video is that there is a fairly good wind. It can be heard in the Mic of the video camera, the ripples on the water and waves on the far shore dont strike me as calm conditions. I could be wrong but I have spent a lot of time on the water as a fishing guide in the past, and the water seems to have a fair wind over it. It also appears, it could be an illusion, that the spray from the bullet impact seems to go right and possibly toward the shooter upon settling after every shot, due to wind.

    Quote:
    The question becomes then, does the G7 BC change with velocity, and does it change on the order of 0.02 units?
    Does it change at the speed of sound? After all the bullet is travelling 600m, and for 2 seconds, below the speed of sound. If this is the case, the only solution will be a custom drag model, or to tweak it with different BCs for different ranges, or to use a bullet that fits the existing drag model.

    The bullets BC does change with velocity and it could easily change by more than .02 units at that distance. The bullets velocity is constantly getting slower and the BC is constantly changing as the velocity changes. If the bullet he is using has a BC of .780 that may be good to1000 yards, but will most likely not be a valid number for soloutions at 1800 or 2000 yards. At that distance he was shooting the bullet would be below 1000 fps and is possibly in a state of unstabilized yaw and who knows what else, further affecting the drag and velocity loss of the bullet.

    Shots like that are stretching the boundries of what the typical small arms cartridges can do with calculated predictable accuracy. Thats why Cpl Craig Harrisons 2475 meter and Rob Furlongs 2430 meter shots are so remarkable.
     
  12. bruce_ventura

    bruce_ventura Well-Known Member

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    I guess you can't rule out issues with the scope. The OP ran the elevation adjustment nearly to the limit. The true elevation depends on the calibration of the turrets, which may not be constant over range. Also, optical distortion could be a factor. If the windage adjustment was also far from the optical centerline (possible, depending on bore/receiver/base alignment) then there will be an error due to either pincushion or barrel distortion, if present.
     
  13. Shumba

    Shumba Well-Known Member

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    Bruce makes a great point that has been overlooked. All of what he stated above could be the culprit. Need a emoticon that shows slaping the forehead as in, "Duh, why didnt I think of that!" lol
     
  14. bigngreen

    bigngreen Well-Known Member

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    Your going to need multiple velocity banded BC's to reach that range accurately with Shooter or almost any program out there right now.
    Range is a big issue as well, there are a few hand held units that will be fine at that range.